From a5a2b727c1dd793a1c5766291a4668c73bb253c6 Mon Sep 17 00:00:00 2001
From: bdemsky <bdemsky>
Date: Sat, 20 Jun 2009 10:47:26 +0000
Subject: [PATCH] check in reaching defs analysis

---
 Robust/src/Analysis/ReachingDefs.java | 54 +++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Robust/src/Analysis/ReachingDefs.java

diff --git a/Robust/src/Analysis/ReachingDefs.java b/Robust/src/Analysis/ReachingDefs.java
new file mode 100644
index 00000000..56095d08
--- /dev/null
+++ b/Robust/src/Analysis/ReachingDefs.java
@@ -0,0 +1,54 @@
+package Analysis;
+
+import IR.Flat.*;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.Iterator;
+import java.util.Hashtable;
+
+public class ReachingDefs {
+  /* This methods takes in a FlatMethod and returns a map from a
+   * FlatNode to the set of live temps for that FlatNode.*/
+
+  public static Hashtable<FlatNode, Hashtable<TempDescriptor, Set<FlatNode>>> computeReachingDefs(FlatMethod fm) {
+    Hashtable<FlatNode, Hashtable<TempDescriptor, Set<FlatNode>>> nodetotemps=new Hashtable<FlatNode, Hashtable<TempDescriptor,Set<FlatNode>>>();
+    
+    Set<FlatNode> toprocess=fm.getNodeSet();
+    
+    while(!toprocess.isEmpty()) {
+      FlatNode fn=toprocess.iterator().next();
+      toprocess.remove(fn);
+      
+      Hashtable<TempDescriptor, Set<FlatNode>> tempset=new Hashtable<TempDescriptor, Set<FlatNode>>();
+
+      for(int i=0; i<fn.numPrev(); i++) {
+	FlatNode fnprev=fn.getPrev(i);
+	if (nodetotemps.containsKey(fnprev)) {
+	  Hashtable<TempDescriptor,Set<FlatNode>> prevtable=nodetotemps.get(fnprev);
+	  for(Iterator<TempDescriptor> tmpit=prevtable.keySet().iterator();tmpit.hasNext();) {
+	    TempDescriptor tmp=tmpit.next();
+	    if (!tempset.containsKey(tmp))
+	      tempset.put(tmp, new HashSet<FlatNode>());
+	    tempset.get(tmp).addAll(prevtable.get(tmp));
+	  }
+	}
+      }
+      
+      TempDescriptor writes[]=fn.writesTemps();
+      for(int i=0;i<writes.length;i++) {
+	HashSet<FlatNode> s=new HashSet<FlatNode>();
+	s.add(fn);
+	tempset.put(writes[i],s);
+      }
+
+      if (!nodetotemps.containsKey(fn)||
+          !nodetotemps.get(fn).equals(tempset)) {
+	nodetotemps.put(fn, tempset);
+	for(int i=0; i<fn.numNext(); i++)
+	  toprocess.add(fn.getNext(i));
+      }
+    }
+    return nodetotemps;
+  }
+  
+}
\ No newline at end of file
-- 
2.34.1